Dance class in Torquay. Agatha in the centre. c 1904. 'We were like obstreperous flowers — often weeds maybe, but nevertheless all of us growing exuberantly — pressing violently up through cracks in pavements and flagstones, and in the most inauspicious places, determined to have our fill of life and enjoy ourselves, bursting out into the sunlight, until someone came and trod on us. Even bruised for a time, we would soon lift a head again.'

Previously unseen portraits of Agatha Christie are currently on display at Bankside Gallery on the Southbank.

If, like us, the images you're used to seeing of the Queen of Crime bring to mind a kindly, older woman sitting by a typewriter, this exhibition really fleshes out the life story of this most successful of writers. The chronological display shows Agatha's happy childhood, her active youth (rollerskating, surfing), as a mother, wife, heartbroken divorcee and in a happy second marriage. Towards the end, more familiar portraits of the elderly writer are also on display.

As well as the photos, the exhibition offers a unique chance to see a portrait of Christie painted by the Austrian expressionist painter Oskar Kokoschka to mark her 80th birthday. The painting belongs to Christie's grandson, Matthew Prichard, and never usually leaves his house. It's a rather garish creation, and we're not sure we liked it.

The pictures are accompanied by brilliant quotes from the woman who is the world's most widely published author, outsold only by the Bible and Shakespeare. The tidbits of memoir, snatches of interview and laconic aphorisms tell Christie's life story beautifully.

Events, from the unusual to the mundane, are reflected upon with searing honesty, emotional intelligence and occasional wit: the arrival of a puppy on her fifth birthday, her parents' deaths, the moment working in a war dispensary when, surrounded by poisons, she thought about writing a detective story.

We rather like Christie's bold, active side too: the rollerskater, adventurer and skimpy-suited surfer are a world away from the 'granny with a typewriter' we've always been shown before.

There's heartbreak too: both wars affect our heroine deeply. The almost paparazzi-style shot of Christie 'discovered' leaving a spa hotel 11 days after going missing following a breakdown is also on display.

While Unfinished Portrait isn't a groundbreaking show, it's certainly a treat for fans and newcomers to the Christie story alike.

Agatha playing a mandolin. c 1898. 'I am today the same person as that solemn little girl with pale flaxen sausage-curls. The house in which the spirit dwells, grows, develops instincts and tastes and emotions and intellectual capacities, but I myself, the true Agatha am the same.'Paris. 1906. 'My first love was music -- I wanted to be a pianist -- I studied piano and singing in Paris... I was very disappointed when I found out that I would never be good enough to be a professional -- my voice was not strong enough for opera and I was too nervous to succeed as a pianist.'Agatha (in centre) Roller-skating on Torquay pier with the Lucy family. c 1911. 'Roller-skating on the pier was a pastime much in vogue. The surface of the pier was extremely rough and you fell down a good deal, but it was great fun.'Agatha -- top row third from left. With soldiers holding Princess Mary’s Christmas gift. Torquay,1914. 'Why not make my detective a Belgian? I thought. There were all types of refugees. How about a refugee police officer? A retired police officer. Not too young a one. What a mistake I made there. The result is that my fictional detective must really be well over 100 by now.'Setting off on a world tour with Archie as part of a trade delegation for the Empire Exhibition, aboard RMS Kildonan Castle from Southampton. January 1922. 'Now there loomed before us a luxury tour indeed... everything in first class style. Nothing but the best was good enough for the British Empire Exhibition Mission. We were what would be termed nowadays VIPs.'Surfing in Muizenberg. 7 February 1922. 'That rushing through the water at what seems to you a speed of about 200 miles an hour; all the way in from the far distant raft, until you arrived, gently slowing down, on the beach... It is one of the most perfect physical pleasures that I have known.'Honolulu, 1922. 'A wonderful, skimpy, emerald green wool bathing-dress which was the joy of my life, and in which I thought I looked remarkably well. Archie thought I did too.'15 December 1926. First press sighting of Agatha leaving The Harrogate Hydro spa hotel after going missing for 11 days. 'I felt like a fox, hunted, my earths dug up and yelping hounds following me everywhere. I had always hated notoriety of any kind, and now I had had such a dose of it that at some moments I felt I could hardly bear to go on living.'Agatha (age 59) by Angus McBean, 1949. Agatha at Greenway. By Svend Aage Dantoft. 1967. 'Oh, I’m an incredible sausage machine, a perfect sausage machine! I always think it must end soon, then I’m so glad when the next one comes along and it’s not so difficult to think of something new after all.'